Summary

Events that are associated with trauma and fear often leave memories that reoccur spontaneously, leading to excessive fear, anxiety, and, in some cases, posttraumatic stress disorder. Such relapses of fear memories constitute a major clinical problem, and their elimination is a major cornerstone of psychological therapy. Many neurobiological studies are therefore focused on understanding how fear memories are controlled (1). On page 1258 of this issue, Gogolla et al. (2) take an important step in the field by determining that the extracellular environment in a particular region of the brain—the amygdala—is responsible for making fear memories erasure-resistant.